Boron overdose, Toxic effects of excess intake

Toxic effects appear at intakes of about 100 mg. The World Health Organization
has banned boron (in the form of boric acid) as a food additive and preservative.
Toxic effects include a red rash with weeping skin, vomiting, diarrhea
characterized by a blue green color, depressed blood circulation, coma and
convulsions. A fatal dose in adults is 15 to 20 g and in children 3 to 6 g. Repeated
intakes of small amounts can cause accumulative toxicity.